Prostaglandin is a physiologically active substance derived from a polyunsaturated fatty acid, and has various important pharmacological and physiological actions at a very small amount, and therefore, various derivatives thereof have been synthesized and developed for medicine. For example, derivatives of prostaglandin F2α are useful as a medicament for treating glaucoma or ocular hypertension, and some eye drops have already been developed and marketed. However, in order to prepare an aqueous preparation of a derivative of prostaglandin, we should overcome some problems that prostaglandin and a derivative thereof are poorly soluble m water and, when dissolved in water, they are easily degraded, and further a content of prostaglandin and its derivative is reduced due to adsorption onto a container.
So far, as an aqueous liquid preparation of prostaglandin or a derivative thereof, for example, a composition obtained by solubilizing and stabilizing prostaglandin by formation of a complex with etherized cyclodextrin (see Patent Document 1), a fat emulsion of a stable PGE1 analogue (see Patent Document 2), a prostaglandin composition containing a polyethoxylated castor oil (see Patent Document 3), a prostaglandin fat emulsion containing an purified olive oil, phospholipid and water, which can be intravenously administered (see Patent Document 4), and an eye drop containing a prostaglandin derivative in which a nonionic surfactant and/or an antioxidant is blended (see Patent Document 5) are disclosed.
Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. H01-221317 (corresponding to EP330511)
Patent Document 2: JP-A No. H07-10833
Patent Document 3: JP-A No. H11-500122 (corresponding to WO97/029752)
Patent Document 4: JP-A No. 2001-10958
Patent Document 5: JP-A No. 2002-161037 (corresponding to EP1321144)